Chemistry instructors in teaching laboratories provide expert modeling of techniques and cognitive processes and provide assistance to enrolled students that may be described as scaffolding interaction. Such student support is particularly essential in laboratories taught with an inquiry-based curriculum. In a teaching laboratory with a high instructor-to-student ratio, mobile devices can provide a platform for expert modeling and scaffolding during the laboratory sessions. This research study provides data collected on the effectiveness of podcasts delivered as needed in a first-semester general chemistry laboratory setting. Podcasts with audio "and" visual tracks covering essential laboratory techniques and central concepts that aid in experimental design or data processing were prepared and made available for students to access on an as-needed basis on iPhones[R] or iPod touches[R]. Research focused in three areas: the extent of podcast usage, the numbers and types of interactions between instructors and student laboratory teams, and student performance on graded assignments. Data analysis indicates that on average the podcast treatment laboratory teams accessed a podcast 2.86 times during the laboratory period during each week that podcasts were available. Comparison of interaction data for the lecture treatment laboratory teams and podcast treatment laboratory teams reveals that scaffolding interactions with instructors were statistically significantly fewer for teams that had podcast access rather than a pre-laboratory lecture. The implication of the results is that student laboratory teams were able to gather laboratory information more effectively when it was presented in an on-demand podcast format than in a pre-laboratory lecture format. Finally, statistical analysis of data on student performance on graded assignments indicates no significant differences between outcome measures for the treatment groups when compared as cohorts. The only statistically significant difference is between students who demonstrated a high level of class participation in the concurrent general chemistry lecture course; for this sub-group the students in the podcast treatment group earned a course average that was statistically significantly higher than those in the lecture treatment group.